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UNITED STATES PATENT Erich,

THOMAS R. CLARK, OF NEW YORK, N. Y.

TANNING HlDES AND SKlNS.

SPECIFICATION forming part of Letters Patent No. 331,942, dated December 8, 1885.

Application filed May 9, 1885. Serial No. IG4,961. (No-specimens.)

T 0 all whom it may concern:

Be it known that I, THOMAS R. CLARK, of the city, county, and state of New York,have invented a new and useful Improvement in Tanning Hides and Skins; and I do hereby declare that the following is a full and exact description thereof.

Hy invention relates to the tanning of hides or skins, and has for its object to reduce the time ordinarily required in the process, with economy in labor and materials, and an improvement in the quality of leather produced. It is applicable more particularly to the preparation of skins for gloves, but it may be advantageously employed in the manufacture of all descriptions of fine leather, and to the tawing of skins with the hair or wool on.-

It consists in the treatment of hides or skins by means of a compound of oil and potash, or other equivalent alkali in manner as follows: The hides or skins may be soaked and unhaired by any of the depilating processes known to the art, and may be taken directly from the drench or bate for treatment by my process. The skins in their wet or, soft state are then coated upon one or both sides with a compound which I obtain by dissolving carbonate of potash in water in the proportions of about eight pounds of the potash to twentyfive gallons of water, and adding to the solution about fifteen gallons of animal oil, using by preference fish-oil or neats-foot oil. The skins are dipped in the compound (or it is otherwise applied to one or both faces thereof) and then placed in stocks or in a revolving drum, or otherwise worked or milled long enough to cause the compound to partially penetrate the skins. They are then taken out and hung up,and thus exposed to the air until they begin to dry, and then returned to the drum or stock to be reworked as before and again hung up. When dried sufficiently after this reworking, another coating of the compound is applied, and the skins are again milled. The operation of milling and drying is thus repeated from five to eight times, depending upon the thickness and character of the skins, until they are thoroughly impreg nated with the compound, and thereby fully tawed. Where the skins are to be finished with the hair or wool on,they are first softened, or they may be taken in their fresh green state.

The compound is applied to the flesh side of the skins, and they are then repeatedly milled and partially dried, as above described, until thoroughly tawed.

Although I have found carbonate of potash and fish-oil to be respectively the cheapest and consequently most desirable materials for my compound, I may use in my process heatsfoot or other oils containing a large percentage of oleine as an equivalent for the fish-oil, and caustic potash, soda, or ammonia as an equivalent for the carbonate of potash.

The proportions of the oil, alkali, and water used in my process may be varied without impairing the efficiency of the compound or departing from my invention, and are necessarily varied where a stronger alkali is used as an equivalent for the carbonate of potash. The proportion of water is also varied in accordance with the character of the skins, the lighter skins requiring more water in the compound.

My improved process saves the labor and the loss of from twelve to sixteen days required in the handling and soaking of skins in lime-pits under the customary processes of tawing and tanning; also, the loss of about five days of time and the labor and expense of materials required in the methods of tawing with alum, flour, eggs, salt, &c., after their treatment with the lime, and the timesome three monthsrequired for ripening the leather tawed by said methods,theleather obtained by my new process in eight days being not only of superior strength and pliability, but ready for immediate use Without the necessity of being kept in stock for months to acquire its pliability and elasticity.

In brief, by my process a leather is produced with great economy in two weeks superior to that heretofore produced in four months.

1am aware ofthe fact that a smooth face is produced on the flesh side ofleather or tanned skins which possess an uneven or rough surface,due to the naps or fibers which rise up therefrom, by applying to the flesh side of the leather with a sponge, cloth, or brush an adhesive composition consisting of water, vegetable oil,soap, a gum or glue, and an alkali but this process diifers wholly from that which I have herein described, in that it is applicable only to the leather or tanned skins for the purpose of obtaining a smooth face on the inner side there- I of, and will not subserve the purpose of tawing an untanned or green hide or skin. I am also aware that small skins have been soaked in common wood-ash lye and then rubbed and worked soft, and, finally, after several repetitions of the process, finished by applying sperm-oil to-the flesh side. and then partially I drying, stretching, and reworking the skins I on the beam, as set forth in Mummas patent being coated with a compound of oil and potash, are placed in stocks and milled, and then dried, and when but partially dry are reworked and again recoated, to be worked and dried repeatedly, as before.

I claim as my invention Tanning hides and skins by the repeated application thereto of the within-described compound of carbonate of potash,water, and animal oil, to be ingrained therein and fixed and of December 24, 1861; but my invention dif- I oxidized by repeated workings and intermefers therefrom in that I work into the body of E diate exposures to the air, substantially in the the skin a compound of oil and potash,which, manner and for the purpose herein set forth. being incorporated with the body of the skin, I In testimony whereof Ihave signedmy name is fixed and oxidized therein by exposure to to this specification in the presence of two sub the air, the result beingaskin ingrained with scribing witnesses. an oxidized or fixed oil, a result unattainable by Mulnnias treatment with lye. My inven- THOS. R. CLARK.

\Vitnesses:

HERMANN LERENZ, A. TEYOONNET.

heretofore in use in which the skins are re l tion differs, furthermore, from the processes peatedly soaked in various solutions,and then 1 dried, in that in my process the skins, after 

